import 'package:flutter/widgets.dart';

class CustomWidget extends LeafRenderObjectWidget {
  @override
  RenderObject createRenderObject(BuildContext context) {
    return CustomRenderObject();
  }
}

class CustomRenderObject extends RenderBox {
  @override
  void performLayout() {
    // 实现布局逻辑
  }

  @override
  void paint(PaintingContext context, Offset offset) {
    // 实现绘制
  }

}